Using Vrm - Raymarine DSM300 User Manual

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5.3 Using VRM

The VRM (variable range marker) key is used in Sonar mode to determine the
VRM/EBL
depth and distance-behind-boat of an object on the display. The VRM function is
available on the scrolling sonar display, bottom lock, and zoom windows.
A VRM is displayed as a cross hair with height and width of the display window.
The center of the crosshair is the reference for which depth and distance-behind-
boat are displayed. You can use the context-sensitive cursor to move the VRM
over a particular object.
Depth is displayed, in the system units, on the right hand edge of horizontal line.
In the scrolling sonar and zoom windows depth is measured from the surface
down. In the bottom lock window, depth is measure from the bottom up.
Distance-behind-boat is displayed next to the vertical line, at the top of the
window. The VRM distance units correspond to the depth units assigned in the
system set up parameters you have assigned for your display unit, as follows:
System Depth Unit
Meters
Feet
Fathoms
The distance-from-boat continues to update as your boat moves.
However, the vertical line does not scroll with the scrolling sonar image. If the
display range changes, the VRM adjusts its relative position so that it does not
move out of the visible display area.
When you switch on the VRM, it is displayed at its last position (unless off screen,
in which case it is displayed on-screen).
If the sounder is in split frequency display mode or a zoom window is displayed
with the scrolling sonar image, then the VRM is shown in both windows at the
same position.
If bottom lock is displayed with the scrolling sonar image, the crosshair lines
appear in bottom lock window but not in the scrolling sonar window.
➤
To switch the VRM on, or re-position an off-screen VRM:
1. Press VRM/EBL.
VRM/EBL
The VRM is displayed in its last-used position.
DSM300 Operation with PLUS Series Displays
VRM Distance Unit
meters
feet
feet